The cerebral palsies: a physiological approach.

T he cerebral palsies (CP) are a heterogeneous group of non-progressive motor disorders of the developing brain. By convention, brain injuries occurring at any stage antenatally and postnatally to the age of 2 years are included in the definition of CP. Primary disorders of the spinal cord such as neural tube defects, neuropathies, and myopathies are excluded. Cerebral palsy should be viewed as part of a “continuum of reproductive casualty”, comprising miscarriages, stillbirths, and severe and minor brain injuries. Consequently, the incidence and causes of CP are a matter of great interest since they provide a benchmark of reproductive health. The incidence of CP in developed countries is stable at about 2–2.5/1000 live births. The risk of CP for premature babies is 5–80/1000 live births, though the majority of cases of CP are term born babies (fig 1).